Jean Michel on LeCleac'h horns

<<My guess is that with round horn the afficiency of the tweeter went down from original 107db right? <<

No,not at all;efficiency is normally better with a Lecleac'h profile;
We have to mesure the ET703 ,when Jean-Michel can find time for that, but I'm not sur waterfall will be excellent over 20k because of the need of very specific micro to mesure the right values till 50kHz!
Whatever, quality of horns in general belongs to few factors: surface quality(very smooth) as describe in an old unknown AES paper;
throat quality,specially for round to square for ex. and
expansion quality as respect of the front wave progression as Lecleac'h horns;
vibrations are not so critical since the pics are very small compare to the signal;of course less vibrations is better.
 
fredsonqc said:
Whatever, quality of horns in general belongs to few factors: surface quality(very smooth) as describe in an old unknown AES paper

So smooth is better?

Do you have a comment on this:
The well-polished, glossy horns look great on the pictures and marketing catalogs but they sound “strange”. With complex musical crescendos (and particular at upper mid range) they weep and sound sort of “slips” across the horn. In addition, the well-polished MFH are way more susceptible to let Sound to inherent the signature of the MHF material: more granularity of the horn surface = less influence of the material to the horn. It you take an ultra-light plastic glossy MFH and paint it with a textured paint then it will substantially minimized the coloration of the thin plastic. The best surface for a horn an ultra-soft wood with a lot of wooden hair sticking right into the horn pathway. However, this type of the finishing might be too dumped for the mellow drivers (like Altec for instance). The most optimum all-around is to have a MHF made according to what I call LS+H+St scenario. It means the MFH should have a LOT of soft body and a lot of soft mass with superb damping ability (LS-layer). Then, it comes the H-layers: hard and ultra thin surface crisp. Eventually the St-layer should finish the MFH. The “St” comes form “structured” or some kind of finishing-substitute for the “hair” that I mentioned above. The idea is that Sound should not use horn like absolute bouncing surface but should perceive it in a way in which a good Jewish bagel made: crispy but slightly abrasive outside, however chewy and tender inside. Romy the Cat
 
This is actually an area where some serious research might bring real benefits...

The "pebble" surface from a textured paint is going to create some degree of turbulence on its surface. The question is what is the effect of this turbulence? Likely it will have very little until the frequencies get pretty high. But that is just an intuitive guess, and intuitive guesses have been shown to be wrong in the past!

Otoh, it could have a positive effect WRT those "HOMs" that Dr. Geddes speaks of. That by not providing a regular surface for reflection, so that at very high frequencies the effective "Q" is reduced.

But I think that what the post is talking about is finding a way to make inexpensive horns reasonable, by removing the effects of the thin plastic or other material from the sound. Nothing more than that. Probably not meaningful for a seriously made high quality horn, except to the extent that there may be some issues WRT surface in a horn that can be explored.

Just my 2 cents, ymmv.

_-_-bear
 
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Some of the old wisdom was that rough is better, the turbulence created on the rough surface acted as a sort of damping layer.

I have no idea if it realy worked, but many old horns used a mix of rough/smooth - damped/bare surfaces. It usually was not done over the whole surface, just parts of it.
 
The well-polished, glossy horns look great on the pictures and marketing catalogs but they sound “strange”. With complex musical crescendos (and particular at upper mid range) they weep and sound sort of “slips” across the horn. In addition, the well-polished MFH are way more susceptible to let Sound to inherent the signature of the MHF material: more granularity of the horn surface = less influence of the material to the horn.

Do you hear grass grow ?

that is one of Romy the Cats baseless assertions like many others. Having done both, i can say : there cannot be perceived absolutely no difference between high-gloss, and slightly granulated surface of horns. What matters, is the horn shape and material, and the driver itself. Thats it.

Angelo
 
Hello,

Many experiments were done on that subject by my friend Marco Henry (the French builder of "Musique Concrete" horns ).

The first horns we designed together were build by Marco in a special concrete. I was a fan of Iwata's theories (Iwata was a gun silencers and tunnels designer) I wanted a quite rough surface of the inner walls of the horn. The idea behind that was to emprison a thin air cushion on the surface of the horn . That's why a special concrete with a large sand / mortar ratio was used. The protruding sand grains give a certain roughness to the inner surface. I still own the prototypes at home (even if I don't use them)

http://www.arduman.com/aa/Sayfalar/lecleach/lecleach2/horn.htm

Then Marco Henry tried several materials and different surface textures. He concluded that the important thing was to have the part of the horn near the throat made of very hard material and with a polished state surface. The texture of the front part was found less significative.

This lead to the material and the smooth surface Marco is using today, as we can see on the Jerzual horns:

http://www.musique-concrete.com/Qui_files/Marco&Hugues.jpg

I have to tell that I didn't find myself many difference in the sound but as I was very confident in Marco's ear (and in his wife's ear too) I begun to use his horns having a smooth inner surface.

Best regards from Paris, France

Jean-Michel Le Cléac'h

xyrion said:


So smooth is better?

Do you have a comment on this:
 
Jmmlc said:
Hello,

Many experiments were done on that subject by my friend Marco Henry (the French builder of "Musique Concrete" horns ).

The first horns we designed together were build by Marco in a special concrete. I was a fan of Iwata's theories (Iwata was a gun silencers and tunnels designer) I wanted a quite rough surface of the inner walls of the horn. The idea behind that was to emprison a thin air cushion on the surface of the horn . That's why a special concrete with a large sand / mortar ratio was used. The protruding sand grains give a certain roughness to the inner surface. I still own the prototypes at home (even if I don't use them)

http://www.arduman.com/aa/Sayfalar/lecleach/lecleach2/horn.htm

Then Marco Henry tried several materials and different surface textures. He concluded that the important thing was to have the part of the horn near the throat made of very hard material and with a polished state surface. The texture of the front part was found less significative.

This lead to the material and the smooth surface Marco is using today, as we can see on the Jerzual horns:

http://www.musique-concrete.com/Qui_files/Marco&Hugues.jpg

I have to tell that I didn't find myself many difference in the sound but as I was very confident in Marco's ear (and in his wife's ear too) I begun to use his horns having a smooth inner surface.

Best regards from Paris, France

Jean-Michel Le Cléac'h


I would defer to JMMLC's experience, for the simple reason he's probably heard more variations of his horn than anyone else in the world. He also knows what a given version of a JMMLC horn is intended to sound like - again, due to experience.

I'd like to draw attention to the latest versions of the JMMLC spreadsheet that accomodate the internal flare of the compression drivers, and uses this as a starting-point for the horn expansion, rather than ignoring it. Small misterminations between the compression driver and the horn result in big response deviations. I suspect this is some of the reason when people mix-n-match compression drivers, they're also creating potential misterminations at the compression-driver end, because the internal flare of the compression driver is not being accounted for.
 
Hello,

Here in France, every year, there is more and more "Le Cléac'h basshorns" calculated using my spreadsheet for "quasicylindrical waves horn".

One of the latest Le Cleach bass DIY horn built is operationnal in Jean-Paul X. 's auditorium. See:

http://nsm01.casimages.com/img/2009/05/17//090517055721545253677910.jpg

Generally, such bass horns are used below 200Hz max but this one is used below 350Hz. Listening impressions done by sveral audiophiles from forum Haute-fidelite.net reported an extraordinary bass register with very low audible distortion and, more surprisingly an exceptionnaly good low mid register.

Here is the frequency response of the bass horn only (with and without equalization below 35Hz:
http://zepload.com/images/1242489777_estrade D 0cm & cor.jpg


Here is the response + distortion (H2 and H3) of the bass horn wthout equalization:

http://zepload.com/images/1242565693_Disto 0cm estrade sans cor.jpg


Listening report and discussions in French at:
http://forums.delphiforums.com/HAUTE_FIDELITE/messages/?msg=30479.1

(requires free prior suscribing)

The spreadsheet to calculate such basshorn is downloadable for free on my friend Nicolas Davidenko's website.
http://ndaviden.club.fr/index.html

Direct link for the spreadsheet (actually it is not the latest version but profile it is quite the same) :
http://ndaviden.club.fr/outils/cylind.zip

Best regards from Paris, France

Jean-Michel Le Cléac'h
 
Wondering if that is a single driver per channel?
What are the T/S params for it/them?
Xmax?
How much power is being used to run them?
What is the reference sensitivity?
(I would assume that one would have to run a speaker of known sensitivity and then compare at some distance and frequency?)

Just curious, I don't have an appropriately sized space to build such a thing... :bawling:

_-_-bear
 
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He has a big room - 70 sq meters, or about 750 sq. ft.

What's the bass driver? Looks like he is running a Haffler amp and doing a big of EQ with the DEQ2496.
Got a JBL2782 on the 8 cell horn (that's a 2" driver so he must have an adapter.) JBL tweeter.

Sure would like to know what bass driver he's using.